How about mixing R-12 with R-134A?


  #1  
Old 08-21-05, 11:50 AM
idoit2
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How about mixing R-12 with R-134A?

I have a 1991 Chevy Berretta, V6, 3.1 L that I inherited from my wife years ago (beauties of marriage : )
In the midst of 90 degree heat the A/C stopped producing cold air and since the fan is working, Iím assuming that the refrigerant is out. So I rushed to my local mechanic and found out that he charges $60/lb for 12-R refrigerant. I passed on that and found a retrofit kit that converts the old 12-R system to the new R-134A.

After much aggravation I found out that the only way to reach the high-side service port on the compressor is to crawl underneath and scrape my face against the low chassis.
I plugged in the gauge and noticed that thereís pressure in the compressor.

My question is, do I absolutely need to recover the old 12-R refrigerant before recharging the system with the R-134A? What are the implications of mixing the two?

Thanks much.
 
  #2  
Old 08-21-05, 12:10 PM
E
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Can't mix the two, r12 is much colder than r134a. You have leak and that needs to be addressed if not you will continually work on the system. If you happen to live near the Mexican border they sell r12 for about 5/6 dollars a pound so you could jump down there and have it fixed really cheap.
 
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Old 08-21-05, 01:22 PM
C
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I believe that is the low side service port, not the high side. Did you read the pressure with the car running (a/c turned on) or not. If not, what was your pressure reading and what was the ambient temp outside. It is against the law to mix the two refridgerants.
 
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Old 08-21-05, 02:15 PM
K
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What you're trying to do is not as simple as the manufacturers of the recharge kit would lead you to believe. The retrofit kit alone does not convert the a/c system. There are a number of things that need to be done to properly convert the a/c system.

First, as easywind mentioned, you need to find why the refrigerant leaked out and fix it, or you'll never have cold air.

R12 and r134 cannot be mixed... they are incompatible and don't work as a mixture.

Along with converting to new r134 refrigerant, you need to add the proper amount of r134-compatible lubricant. You also need to add the new port fittings, and change out the o-rings and receiver/dryer/accumulator to r-134 compatible parts.

Also, a vacuum must be pulled on the system to evacuate all air from the system before recharging with refrigerant.

Any shortcuts you take will result in less than cold air and severely reduce the life of your a/c system.

Still want to do it yourself?...
 
  #5  
Old 08-21-05, 04:40 PM
Ramrod48
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ac

Plus you will get this mixture of GOO , in your system , that will burn up your compresser in a very short time ,, you got MORE MONEY ?
 
  #6  
Old 08-21-05, 08:08 PM
idoit2
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Thanks for all the input.

As I tought it's easier said (as the convertion-kit manufacturer does) than done. The kit's going back and I'm way far from the Mexican border. I'll deal with the natural heat.
 
  #7  
Old 08-22-05, 06:40 AM
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DIY a/c repair, including conversion, is possible if you add two items to your tool set -- a vacuum pump and an a/c manifold gauge set. Depending on how comfortable you are performing automotive repair, we can walk you through the repair if you have access to these tools.
 
  #8  
Old 08-22-05, 02:32 PM
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Exclamation Check your electronics first!

You didn't mention if the compressor was engaged. If not, you may not need the hassle of a recharge. The surest way to determine this is a high side pressure check and/or a visual to determine if the compressor clutch is engaging when you turn on the AC. If you watch the compressor while someone else turns on the AC, you may be able to notice if the driven side of the compressor starts turning. The fan that circulates the air is no indication that the compressor is operating. Neither is the blue(or other color) AC light.
 
  #9  
Old 08-25-05, 11:07 PM
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I cant say enough for the retro kit ive done it on three different vehicles with great success. all i changed were the conversion fittings pulled a vaccum and shot it up, one of the three i own still works been three years.
 
 

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